Is it permissible to have more than one intention for a single act, such as sending adhkar and supplications to people, or giving water as charity with the intention of reward for the donor and their living and deceased relatives?

It is permissible to perform acts of obedience with more than one intention, such as praying two rak'ahs with the intention of greeting the mosque, seeking guidance (istikharah), performing ablution, and repentance. A person is rewarded according to their intention and determination, for the Prophet, peace and blessings be upon him, said: "Indeed, actions are by intentions, and indeed, every person will have what he intended." Similarly, it is valid to dedicate the reward to more than one person.